Remove Times trait

`Times::times` was always a second-class loop because it did not support the `break` and `continue` operations. Its playful appeal was then lost after `do` was disabled for closures. It's time to let this one go.

src/libextra/json.rs

@@ -282,7 +282,7 @@ fn escape_str(s: &str) -> ~str {
 
 fn spaces(n: uint) -> ~str {
     let mut ss = ~"";
-    n.times(|| ss.push_str(" "));
+    for _ in range(0, n) { ss.push_str(" "); }
     return ss;
 }